Process of converting sultones to hydroxyalkylsulfonates

ABSTRACT

1. A PROCESS FOR CONVERTING SULTONES INTO HYDROXY ALKANE SULFONIC ACID SALTS IN HIGH PURITY AND HIGH YIELD WHICH COMPRISES REACTING A SULTONE OF THE FORMULA:   O&lt;(-C(-R)(-R&#39;&#39;)-(C(-R)2)N-C(-R)(-R&#34;)-SO2-)   WHEREIN: R, R&#39;&#39; AND R&#39;&#39;&#39;&#39; ARE HYDROGEN OR ALKYL, N IS AN INTEGER OF 0, 1, 2, OR 3, THE TOTAL NUMBER OF CARBON ATOMS IN THE SULTONE MOLECULE IS FROM ABOUT 6 TO ABOUT 40, WITH ALKALI METAL HYDROXIDE OR ALKALINE EARTH METAL HYDROXIDE, IN N ANHYDROUS SYSTEM, AT A TEMPERATURE OF FROM ABOUT 75 TO ABOUT 250* C., THE HYDROXIDE AND SULTONE BEING USED IN A RATIO OF FROM ABOUT 1.1 TO ABOUT 25 MOLS OF ALKALI METAL HYDROXIDE, OR FROM ABOUT 0.55 TO ABOUT 12.5 MOLS OF ALKALINE EARTH METAL HYDROXIDE, PER MOL OF SULTONE.

United States Patent 3,849,486 PROCESS OF CONVERTING SULTONES TOHYDROXYALKYLSULFONATES Gerhard O. Kuehnhanss, Baton Rouge, La., assignorto Ethyl Corporation, Richmond, Va. No Drawing. Filed May 3, 1973, Ser.No. 356,907 Int. Cl. C07c 143/02 US. Cl. 260-513 R Claims ABSTRACT OFTHE DISCLOSURE It is disclosed that sultones are converted to salts ofhydroxy alkyl sulfonic acids by reaction in an anhydrous system with anexcess of base.

FIELD OF THE INVENTION This invention relates to the preparation ofhydroxy alkyl sulfonic acid salts and of selected mixtures thereof withalkene sulfonic acid salts.

BACKGROUND For the most part, the prior art conversion of sultones intosulfonic acid salts has been conducted in one or more steps under a widevariety of conditions emphasizing high temperatures because of thedifficulty of hydrolysis of sultones. Some of the prior art involvesmore or less critically timed complex step sequences with strongreagents. Examples of known operations are given in U.S. Pats.2,061,617; 2,187,244; 3,642,881; and 3,496,225.

Much of the prior art emphasis in connection with the sulfonation ofa-olefins to produce olefin sulfonate salts is centered about aqueouscaustic hydrolysis treatment of S0 sulfonation efiluent acid-mixcontaining about 25-60 percent sultones, the balance being mostlysulfonic acids. When such an acid-mix is subjected to basic hydrolysiswith aqueous NaOH, it is usually considered that there is produced themixtures described in U.S. Pat. 3,332,880 as containing about 30-70percent alkene sulfonic acid salts, about -70 percent hydroxy alkylsulfonic acid salts and about 2-15 percent disulfonate salts. Much ofthe prior art favors sulfonation procedures using uncomplexed S0 sincethese procedures are considered to be conducive to the formation ofpreferred 3-hydroxy alkane sulfonic acid salts rather than generallyless desired Z-hydroxy alkane sulfonic acid salts.

Olefin sulfonation processes are known to co-produce disulfonates andhigher order polysulfonates in appreciable quantities. For example,compositions of US. 3,332,- 880 are indicated as containing about 2-15percent disulfonates. In some instances disulfonates are undesired inliquid detergent compositions because of their highly polar nature.Usually one can minimize the production of disulfonates to some extentby controlling the mol ratio of 50;, to olefin used in the sulfonationstep. Where the SO :olefin ratio is about 1:1 or less, the amount ofdisulfonates is generally less than it is with higher SO :olefin ratios.On the other hand, SO :olefin ratios of about 1:1 and lower result inthe failure of some olefin molecules to be sulfonated. Generally, theknown prior art practice accepts about 10 percent disulfonates as areasonable compromise with free oil content (unsulfonated olefin orparatfins) in the sulfonation product and prefers S0 to olefin molratios of from about 1.05:1 to about 1.25:1.

SUMMARY OF THE INVENTION In accordance with the present invention, aprocess is provided whereby sultones are converted virtually completelyto hydroxy alkyl sulfonic acid salts. High purity of product and highyield are attained.

Surprisingly, this result is attained by performing the aforesaidconversion in a substantially anhydrous system 'ice using an excess of astrong base and moderate temperatures. Preferably, the process isperformed in the presence of an inert non-aqueous diluent that isreadily removed when its presence is no longer desired. Avoidance ofexcessively high temperatures usually is desirable to minimize undesiredside reactions such as conversion of the sultones to alkene sulfonicacid salts.

Accordingly, the present invention provides a process for convertingsultones into hydroxy alkyl sulfonic acid salts which comprises reactinga sultone with an excess of anhydrous base at a temperature of fromabout to about 250 C. Preferred sultones have from about 6 to about 40carbon atoms per molecule. Preferably the temperature is from about toabout 200 C., especially from about to about C. and the reaction is inan anhydrous system. Preferably, the base is an alkali metal hydroxideor an alkaline earth metal hydroxide, particularly the former. Typicalbases include calcium hydroxide and magnesium hydroxide. Particularlypreferred bases are sodium hydroxide and potassium hydroxide, singly orin admixture with each other or with other bases. Sodium hydroxide isgenerally preferred because of low cost, availability and excellentproperties of the resultant sodium compositions.

The process preferably is conducted in an inert organic solvent for thesultone. -Aprotic solvents such as cyclic and acyclic olefins, paraflinsor aromatic hydrocarbons are generally preferred because of their inertnature, good solvent properties, low cost and ready availability.Preferred solvents are paraflinic hydrocarbon solvents. Other preferredsolvents are aromatic hydrocarbon solvents. Other preferred solvents areolefinic hydrocarbon solvents. Typical solvents are hexane, octane,nonane, decane, undecane, dodecane, tridecane, tetradecane, and olefinsof similar numbers of carbon atoms per molecule. Other typical solventsare toluene, xylene, and Decalin.

In a preferred aspect, the process of the invention uses sodiumhydroxide and the reaction is conducted in an inert hydrocarbon solventfor the sultone.

An acid mix formed by sulfonating an olefin or an olefin mixture with S0provides a preferred source of sultones for use in the present process.The sultones may be recovered from such an acid-mix by crystallizationfrom a hydrocarbon solvent, or by such alternate methods as solventextraction. This provides a suitably concentrated sultone startingmaterial for the present process. By reacting such sultones with excessanhydrous base according to the present process, products are obtainedhaving a high percentage content of hydroxy alkyl sulfonic acid salts,virtually 100 percent. The conversion is virtually quantitative.

In addition to the foregoing, one may obtain more or less pure sultonesor mixtures containing pure individual or mixed sultones in other Ways.For example, processes that produce sultones are described in US. Pats.2,094,- 451; 2,187,244; 2,850,507; 3,117,133; 3,146,242; 3,164,- 608;3,164,609; 3,200,127; 3,205,237; 3,332,880; 3,376, 336; 3,524,864;3,579,537 and in Canadian Patent 894,830, and in the references cited insaid patents; all of which, like other reference material cited herein,are herewith incorporated herein by reference.

Sultones useful in the process of the present invention are of thegeneral formula:

-- l (CRz)n(:JR O S 02 wherein R, R and R" are hydrogen or alkyl and nis a whole number integer of 0, 1, 2 or 3. In such sultones generally atleast one of the R groups, such as R and R is a hydrocarbon group suchas alkyl, alkenyl, aralkyl, alkaryl and is unsubstituted or has onlyhydroxy or sulfonate (SO substitution. In addition, two or more of the Rgroups also may be linked together in cyclic carbon chain structures andmolecules may contain more than one (-SO structure. Such sultones arewell known to those skilled in the art as evidenced by the patents citedherein.

In preferred sultones having from about 6 to about 40 carbon atoms permolecule, 11 is 1 or 2, R and R are hydrogen and R is alkyl of fromabout 2 to about 37 carbon atoms. More preferred sultones have fromabout to about 24 carbon atoms per molecule and R has from about 6 toabout 21 carbon atoms. In particularly preferred sultones having fromabout 12 to about carbon atoms per molecule, R has from about 8 to about17 carbon atoms. Such sultones in which n =1 are especially preferred.

Particularly useful sultone mixtures contain molecules whose carbonchain units contain predominantly the following numbers of carbon atoms:12 and 14; 12, 14 and 16; 14 and 16; 14, 16 and 18; 16 and 18; 16, 18and 20; 11, 12, 13, 14, and 15; 12, 13 and 14; 11, 13 and 15; 15, 16, 17and 18; 15, 17 and 19 and 17, 19 and 21, and the like. These differentcompositions result in the production of sulfonate salts having desiredsurfactant properties in various water hardnesses, at differenttemperatures and for cleaning various materials in liquid formulationsas well as in solid formulations.

The carbon skeleton structures of preferred sultones are saturated andare straight chain or branched chain, cyclic or aromatic or combinationsof such structures, and which are pure or in mixtures. Thus mixturesobtained by converting sultones to sulfonic acid salts in accordancewith the teachings of the present invention can contain entirelystraight or branched or cyclic carbon chain units or other structures orcombinations in various proportions. In general, preferred sultones usedfor the process contain from about to about 100 percent of moleculeshaving open chain carbon skeleton.

The positions of linkage to the carbon chain in starting sultones can beat various combinations of terminal and internal carbon atoms or atinternal carbon atoms. Usually mixtures contain various isomers, butstructures in which the S of the sultone is linked to a terminal carbonpredominate.

A typical acid mix containing sultone and sulfonic acid, useful forrecovery of sultone starting material, is obtained by sulfonating amixture of olefins with uncomplexed 80;, in a mol ratio of S0 to olefinof from about 0.5 :1 to about 2:1, said olefins containing 0 to 100percent vinyl, and/ or 0 to 100 percent internal olefins and in whichvinylidene olefins may be present, said olefins having from about 6 toabout 40 carbon atoms per molecule. Unreacted olefin from suchsulfonation is frequently a suitable solvent both for crystallization ofthe starting sultone and for the subsequent reaction of the sultone withanhydrous base according to the process of the present invention. Wheredesired, sultones can be obtained from such an acid-mix using variousprocesses such as crystallization solvent extraction and the like.

A mixture of sultones containing one or more components having (1)various numbers of carbon atoms per molecule, (2) various carbonskeleton structures and/or (3) various positions of S0 linkages to thecarbon skeleton structure is generally preferred because such mixturescan be obtained readily by sulfonating mixtures of olefins available inlarge quantities and at low cost. Preferably such starting olefinmixtures are selected to produce product sulfonic acid salt havingdesired properties for the ultimate use either per se or in combinationwith various other sulfonate materials and adjuvant materials generallyused in surface active compositions such as dishwashing or laundrydetergents.

Although the conditions and materials used in sulfonation are important,the various materials and other factors involved such as temperature,pressure, proportions, diluents, reactor configuration, contact time,etc. are Well known to those of skill in the art. As an example, olefinsmay be sulfonated with 80;, in a falling-film reactor at a temperatureof from about 0 to about C., at a SO /olcfin mol ratio of from about0.5:1 to about 2:1. Preferred temperatures are about 40-50 C. while thepreferred SO /olefin mol ratio is from about 1.0:1 to about 1.2:1.Typical batch-wise pot reactor sulfonations and conditions therefore aredisclosed in US. Pat. 2,061,617.

Typical sultones processed in accordance with the present inventioninclude: 3 hydroxydecane 1 sulfonic acid sultone, 4hydroxydecane-l-sulfonic acid sultone, 3 hydroxyundecane 1 sulfonic acidsultone, 4-hydroxyundecane 1 sulfonic acid sultone, 3-hydroxydodecane- 1sulfonic acid sultone, 4 hydroxydodecane-l-sulfonic acid sultone, 3hydroxytridecane 1 sulfonic acid sultone, 4 hydroxytridecane 1 sulfonicacid sultone, 3 hydroxytetradecane 1 sulfonic acid sultone, 4hydroxytetradecane 1 sulfonic acid sultone, 3 hydroxypentadecane 1sulfonic acid sultone, 4 hydroxypentadecane 1 sulfonic acid sultone, 3hydroxyhexadecanel-sulfonic acid sultone, 4 hydroxyhexadecane 1 sulfonicacid sultone, 3 hydroxyheptadecane 1 sulfonic acid sultone, 4hydroxyheptadecane 1 sulfonic acid sultone, 3 hydroxyoctadecane 1sulfonic acid sultone, 4 hydroxyoctadecane 1 sulfonic acid sultone, 3hydroxynonadecane 1 sulfonic acid sultone, 4 hydroxynonadecane 1sulfonic acid sultone, 3 hydroxyeicosane 1 sulfonic acid sultone, 4hydroxyeicosane-l-sulfonic acid sultone, 3 hydroxyheneicosane 1 sulfonicacid sultone, 4 hydroxyheneicosane 1 sulfonic acid sultone, 3hydroxydocosane 1 sulfonic acid sultone, 4 hydroxydocosane 1 sulfonicacid sultone, 3-hydroxytricosane 1 sulfonic acid sultone, 4hydroxytricosanel-sulfonic acid sultone, 3 hydroxytetracosane 1 sulfonicacid sultone.

Typical hydroxy alkane sulfonic acids whose salts are produced fromsultones in accordance with the present invention include3-hydroxy-decane-l-sulfonic acid, 4-hydroxy-decane-l-sulfonic acid,S-hydroxy-decane-l-sulfonic acid, 3-hydroxy-undecane-l-sulfonic acid,4-hydroxy-undecane-l-sulfonic acid, 5-hydroxy-undecane-l-sulfonic acid,3-hydroxy-dodecane-l-sulfonic acid, 4-hydroxy-dodecane-l-sulfonic acid,5-hydroxy-dodecane-l-sulfonic acid, 3-hydroxy-tridecane-l-sulfonic acid,4-hydroxy-tridecanel-sulfonic acid, S-hydroxy-tridecane-l-sulfonic acid,3-hydroxy-tetradecane-l-sulfonic acid, 4-hydroxy-tetradecane-l-sulfonicacid, S-hydroxy-tetradecane-l-sulfonic acid,3-hydroxy-pentadecane-l-sulfonic acid, 4-hydroxy-pentadecane-l-sulfonicacid, 5-hydroxy-pentadecane-1-sulfonic acid,3-hydroxy-hexadecane-l-sulfonic acid, 4-hydroxy-hexadecane-l-sulfonicacid, S-hydroxy-hexadecane-l-sulfonic acid,3-hydroxy-heptadecane-l-sulfonic acid, 4-hydroxy-heptadecanel-sulfonicacid, 5 -hydroxy-heptadecane-l-sulfonic acid,3-hydroxy-nonadecane-l-sulfonic acid, 4-hydroxy-nonadecane-l-sulfonicacid, S-hydroxy-nonadecane-l-sulfonic acid,3-hydroxy-eicosane-l-sulfonic acid, 4-hydroxy-eicosane-l-sulfonic acid,S-hydroxy-eicosane-l-sulfonic acid, S-hydroxy-heneicosane-l-sulfonicacid, 4-hydroxy-heneicosancl-sulfonic acid,5-hydroxy-heneicosane-l-sulfonic acid, 3-hydroxy-docosane-l-sulfonicacid,

4-hydroxy-docosane-l-sulfonic acid, S-hydroxy-docosane-l-sulfonic acid,3-hydroxy-tricosane-l-sulfonic acid, 4-hydroxy-tricosane-l-sulfonicacid, S-hydroxy-tricosane-l-sulfonic acid,3-hydroxy-tetracosane-l-sulfonic acid, 4-hydroxy-tetracosane-l-sulfonicacid, and S-hydroxy-tetracosane-l-sulfonic acid.

Some of the foregoing and additional sultones and sulfonic acids andother materials useful with the process of the present invention aredescribed in terms of a starting material produced by sulfonation ofvarious individual olefins or olefin mixtures selected from thefollowing listing: decene-l, undecene-l, dodecene-1, tridecene-l,tetradecene-l, pentadecene-l, hexadecene-l, heptadecene- 1,octadecene-l, nonadecene-l, eicosene-l, triacontene-l, 2-ethyl-hexene-1,2-methyl undecene-l, 2-ethyl decene-l, 2-propyl undecene-l, 2-butyldecene-l, 2-pentyl decene-l, 2-hexyl octene-l, decene-2, undecene-3,dodecene-4, tridecene-2, tetradecene-5, pentadecene-7, hexadecene-6,heptadecene-8, octadecene-2, nonadecene-2, eicosene-Z, tricosene-2,3-ethyl-dodecene-2. Sultone derivatives of the vinyl and internalolefins of the foregoing listing are generally of the form 1,2-; 1,3-;1,4-; 1,5-; 2,3-; 2,4-; 2,5-; 2,6- or the like depending upon theprocedures used in sulfonation and on the starting olefin. Vinylideneolefins usually form sulfonic acids rather than sultones. Alkenesulfonic acids, hydroxy alkyl sulfonic acids and disulfonic acids areisomeric in nature depending to some extent upon the predominant form ofthe co-present or precursor sulfones.

The process of the present invention requires an excess of base above a1:1 mol ratio of base to sultone (or sultone plus sulfonic acid). Whenthe amount of excess base is small, generally about percent or less, theconversions are low and losses high. Although base:sultone mol ratios upto about 25:1 are useful, ratios in excess of about 5:1 mols of base permol of sultone are seldom necessary and are preferably avoided tominimize the problems attendant to recovery of the excess base. Thus themol ratio of base to sultone is from about 1.2:1 to about 25: 1,preferably from about 1.25:1 to about 10:1, especially from about 1.5:1to about 5: 1. These specific ratios apply to bases of monovalent alkalimetals and in general are divided by a factor of 2 for bases of divalentalkaline earth metals. Furthermore, the ratios are based on sultoneshaving an average of one sulfonate group (SO per molecule. The mixtureshaving an average of more than one (SO group per molecule requireproportionately larger amounts of base.

The temperature used for the present conversion reaction, although notespecially critical, is important as set forth hereinafter. Thetemperature must be high enough and held long enough to produce thedesired reaction. In general, this requires operation above the freezingpoint of the sultone. On the other hand, temperatures must not be heldat an excessively high value for a sufficiently long time to produce anadverse amount of side reactions. Temperatures of from about 75 to about250 C. are useful with temperatures of from about 100 to about 200 C.being preferred because of equipment cost and other considerations.Reaction times range from a few minutes to several hours, depending tosome extent upon temperature. Suitable pressures range from about 0.1 toabout 100 atmospheres. In general, it is preferred to operate near or atatmospheric pressure or somewhat higher, typically from about V2 toabout 10 atmospheres pressure, to avoid costly high pressure or highvacuum equipment, and to minimize dehydration. Reaction times willnaturally vary depending upon temperature, concentration, and the molratio of base to sultone employed. In particular, when lower mol ratiosof base to sultone are employed, e.g. 1.2-2.0, longer reaction timesand/or higher temperatures are desirable to ensure complete reaction.

As a general proposition, sulfonic acid salts produced by the presentprocess have valuable surface active properties and are useful withother materials in built and in unbuilt detergent formulations known tothose skilled in the art for sulfonic acid salts. For example, US. Pats.3,332,- 874-3,332,880 describe combinations of certain sulfonic acidsalts with alkyl glyceryl ether sulfonates, with alkyl aryl sulfonatesand alkyl ether sulfates, with esters of condensates of coconut fattyalcohols and3(N,N-dimethyl-N-alkylammonio)-2-hydroxy-propane-l-sulfonate, withamides, and with amides and alkyl glyceryl ether sulfonates. The presentproducts are useful in such ways in various forms, such as liquid,flake, granule, tablet and bar form. When used with detergent buildersand other adjuvants, conventional materials and proportions may be usedas set forth for example in US. Pat. 3,332,880, columns 10 and 11,herein incorporated by reference. In general, the proportions of alkenesulfonic acid salts relative to hydroxy alkyl sulfonic acid saltsproduced by the present anhydrous process are different from thoseproduced by aqueous processing since in the present process sultones areconverted almost exclusively to hydroxy alkane sulfonic acid salts andin high yield.

The following examples indicate preferred embodiments and aspects of thepresent invention.

Example I 3 Grams (10.84 mmol) of the sultone of3-hydroxytetradecane-l-sulfonic acid was dissolved in 10 ml. of toluene,3 g. (75 mmol) powdered anhydrous NaOH was added and the slurry heatedslowly to the boiling point (107") with stirring and under theprotection of a stream of dry nitrogen. The system Was held at thistemperature at reflux of 1 hour.

After cooling, the mixture was extracted three times using 25 ml.portions of ether to remove toluene and any unreacted sultone whichmight be present.

The dry residue remaining after removal of the ether was dissolved in 50ml. of a 1:1 mixture of isopropanol and water and the excess NaOHneutralized and brought to a pH of about 8 by adding dilute H 50 10 g.of Na CO was added to the neutralized solution. The solution separatedinto an aqueous phase containing inorganic salts and an organic phasecontaining the saltfree sulfonate. The aqueous phase was set aside.

After evaporation of the isopropanol from the organic phase,hydroxyalkane sulfonate was recovered as a white solid. The recoveredproduct was analyzed by thin layer chromatography -(TLC) using amodification of the procedure described in J.A.O.C.S. Vol. 48, December1971, pages 790-793.

Recovery: 3.15 g. (92.3 percent of theoretical) Purity: 98 percent bythin layer chromatography (TLC) analysis.

Example II 1 g. (3.28 mmol) of the sultone of 3-hydroxy-hexadecane-lsulfonic acid was dissolved in 4 ml. toluene in a flask equipped with areflux condenser. l g. (25 mmol) finely powdered solid NaOH was addedand the mixture was heated slowly to the boiling point of toluene (108C.) with stirring.

After one hour of refluxing and stirring, the viscous mixture was cooleddown to room temperature and the tollluene and unreacted sultone removedby extraction with et er.

The white, finely dispersed, solid residue resulting from the etherextraction was dissolved in 26 ml. of a 1:1 mixture of isopropanol andwater and the strong caustic solution adjusted to a pH between 7 and 8by adding dilute H 50 The mixture was heated to 55. The alcohol andWater phases were separated by adding 4 g. Na CO The aqueous phase wasdischarged. The isopropanol phase was evaporated to dryness.

Recovery: 0.85 =75.2 percent (theory) of a white solid TLC analysis: 2percent alkene sulfonate +98 percent hydroxyalkane sulfonate.

Example III Protected by a nitrogen blanket and with stirring, a drymixture of 2 grams (6.56 mmol) of the sultone of 3- hydroxyhexadecane-lsulfonic acid and 2 grams (50 mmol) powdered solid NaOH was heatedslowly to 160.

After cooling, the reaction mixture was extracted with ether to removeresidual sultone. (No unreacted sultone was found.)

The residue was dissolved in a hot mixture of 25 ml. isopropanol and 25ml. H O.

To this mixture was added 8 grams of Na CO The mixture was agitated andallowed to separate into two layers.

The aqueous, salt-containing layer was discarded, the isopropanol phaseallowed to settle overnight (7 C.).

Snow white crystals had separated from the solution on standing; theywere separated by vacuum filtration, washed, and dried.

A second smaller portion of sulfonate was recovered from the filtrate.

Example IV 40 mmols of the sultone of 3-hydroxydodecane-l-sulfonic acidwas combined with an equal weight of anhydrous, powdered NaOH in 80 ml.dodecane, the reaction mixture brought to 140 (oil bath), and themixture held at this temperature for 2 hours while stirring and passinga stream of dry nitrogen over the slurry.

The reaction mixture thus obtained contained the desired hydroxy alkanesulfonate, the excess NaOH, dodecane and possibly unreacted sultone.Separation schemes for this kind of mixture are based generally on thedifferent solubility of the components in the system: H O/nonmiscibleorganic solvent. Changing from the anhydrous into the aqueous systempresents a problem to avoid hydrolysis of the unreacted sultone leadingto erroneous results. Previous experiments had shown, however, that thesultone does not hydrolyze at low temperature and that little or nounreacted sultone is present, nevertheless, the following technique wasused to avoid the interference described.

200 ml. of a mixture of MEK (methyl ethyl ketene)/ hexane (2:1 byvolume) was added to the cold reaction product and the slurry cooled toC. The excess caustic was dissolved by adding 200 ml. of a (1:1) mixtureof MEK/H O. Dilute H SO was then added to the mixture until a pH around8 was reached. After adding another 200 ml. of the MEK/H O mixture, thesolution was warmed to room temperature and stirred vigorously for 10minutes. On standing the phases separated. The lower aqueous layercontaining the desired sultonate was recovered and extracted three moretimes with 200 ml. portions of (2:1) MEK/hexane. The final, neutral-freeaqueous solution containing only sulfonate and sulfate was evaporated todryness. To remove the sulfate, the dry mixture of salt and sulfonatewas dissolved in a hot mixture (55 C.) of isopropanol/H O (1:1 byvolume) using 25 ml. of the solvent per gram of sulfonate/ salt mixture.

Anhydrous sodium carbonate was added to the clear hot solution until thephases separated (3.5 g. carbonate per gram sulfonate). Thesulfate-containing aqueous layer was discarded. The desired sulfonatewas recovered from the isopropanol phase by evaporation of the solvent.

10.7 Grams of sodium-S-hydroxydodecane sulfonate free of salt and ofneutrals was recovered which was 92.75 percent of theory.

Example V Example IV was repeated using the sultone3-hydroxytetradecane-l-sulfonic acid. 12.0 Grams ofsodium-3-hydroxytetradecane sulfonate free of salt and neutrals wasrecovered which was 94.8 percent of theory. Purity by TLC was 97percent.

Example VI Example IV was repeated using the sultone of3-hydroxyhexadecane-l-sulfonic acid. In this instance four runs weremade each using of the materials and the product from the four runs wascombined.

The recovery procedure was modified slightly at the end since theproduct separated from the isopropanol solution on standing so thatevaporation of the solvent was not needed. After decantation, the endproducts were obtained by vacuum filtration and drying of the cake inair. 10.1 Grams of sodium-3-hydroxyhexadecane sulfonate free of neutralsand salt was recovered. Purity by TLC was 97 percent.

Example VII Example IV was repeated using the sultone of3-hydroxyoctadecane-l-sulfonic acid.

As in Example VI, the product separated from the propanol solution onstanding and was recovered by decantation, vacuum filtration and airdrying. 12.7 Grams of sodium-3-hydroxyoctadecane sulfonate free of saltand neutrals was recovered. This was only 85.2 percent of theory;however, in this instance the mother liquor was discharged withoutrecovery of the residual product contained therein. Purity by TLC was 89percent.

Example VIII A series of runs was conducted as in Example VI at varioustemperatures, various reaction times and various ratios of base tosultone.

The runs were based on 3 gram quantities (9.85 mmols) of a typicalsultone, the sultone of 3-hydroxyhexadecanel-sulfonic acid. The baseused was NaOH, the mol ratio of base to sultone ranged from 1.0 to 15.2.Reaction time ranged from 0.5 to 3 hours. Temperature ranged from to 180C. The reaction was conducted in anhydrous systems using dodecane as atypical solvent.

Results are tabulated. Runs 6 and 7 are included to show the results ofoperating outside the scope of the present invention, i.e., without anexcess of anhydrous base.

Mol Na- Recovery Composition by TLL, OH per sulfonate wt. percent" RuTemp, Time, mol moi No. 0. hrs. sultone percent A- HA X NaOHzSultone=L9to 15.2

NaOHzSultone=1 NaOH: Sultone=1.5 to 2.3

Calc. for 100 percent HA.

"Ar, HA and X mean, respectively, alkene sulfonate, hydroxy alkylsulfonate and unknown, The unknown probably is an intermediate 0! somesort associated with incomplete reaction.

What is claimed is:

1. A process for converting sultones into hydroxy alkane sulfonic acidsalts in high purity and high yield which comprises wherein:

R, R and R" are hydrogen or alkyl, n is an integer of 0, 1, 2, or 3, thetotal number of carbon atoms in the sultone molecule is from about 6 toabout 40, with alkali metal hydroxide or alkaline earth metal hydroxide,in an anhydrous system, at a temperature of from about 75 to about 250C., the hydroxide and sultone being used in a ratio of from about 1.1 toabout 25 mols of alkali metal hydroxide, or from about 0.55 to about12.5 mols of alkaline earth metal hydroxide, per mol of sultone.

2. The process of Claim 1 wherein the mol ratio of hydroxide to sultoneis from about 1.2 to about 25 for alkali metal hydroxide or from about0.6 to about 12.5 for alkaline earth metal hydroxide.

3. The process of Claim 1 wherein the temperature is from about 100 toabout 200 C.

4. The process of Claim 1 wherein the sultones have from about 10 toabout 24 carbon atoms per molecule.

5. The process of Claim I conducted in the presence of an inert solventfor the sultone.

6. The process of Claim 5 wherein the solvent is a paraffinichydrocarbon solvent.

7. The process of Claim 5 wherein the solvent is an aromatic hydrocarbonsolvent.

8. The process of Claim 5 wherein the solvent is an 01efinic hydrocarbonsolvent.

9. The process of Claim 1 wherein the sultone is reacted with alkalimetal hydroxide.

10. The process of Claim 1 wherein the alkali metal hydroxide is sodiumhydroxide.

References Cited UNITED STATES PATENTS 2,860,144 11/1958 Wirth 260513 R2,511,043 6/1950 Busch 260513 R FOREIGN PATENTS 1,498,638 10/ 1967France 260513 R BERNARD HELFIN, Primary Examiner N. CHAN, AssistantExaminer

1. A PROCESS FOR CONVERTING SULTONES INTO HYDROXY ALKANE SULFONIC ACIDSALTS IN HIGH PURITY AND HIGH YIELD WHICH COMPRISES REACTING A SULTONEOF THE FORMULA: